Natural whetstone SOTC and stone finishes
I figured it's about time to show off the tools that keep my knives looking and performing well. Aside from a few bench size ones I want to eventually try, I see my future with JNATs with koppa, especially with finding underrated bargain pieces or trying out examples from mines that don't get as much attention.
I've been spending several months practicing and refining my polishing technique, so hopefully these pictures also serve as a good reference for the various finishes they put on. All finishes were done on a flattened kiridashi with slurry generated from an atoma 600.
As a caveat, every natural stone is different and getting a consistent kasumi requires more knowledge and skill than the stone itself. For those who are curious about JNATs, I strongly encourage establishing your polishing fundamentals first, before easing into koppa size stones.
The stones:
Pic 1 - Bench and koppa size stones (from left to right) - Top row
- Natsuya
- Large vintage piece, excellent particle uniformity, definitely on par with synthetics. Great for adding bite to an edge. Stropping on this with the Okudo shiro suita is a great way to touch up a blade and minimize the amount of steel being taken off.
- Aka Amakusa
- My coarsest stone in the JNAT lineup. Gorgeous torato pattern, but can get scratchy. Mainly used to establish coarse edges that take too long on the Natsuya.
- Shiro Amakusa
- Finer than the Amakusa or Natsuya, can clog up relatively easily. This one is considered as a Nakatoishi, however the slurry can break down to super fine particles, leaving you with a finish that Awasedo usually produce.
- Kozaki Aoto (koppa)
- Small but mighty - medium hard aoto that cuts rather quickly, puts on a dark kasumi
- Kozaki Aoto (bench)
- The koppa was so good that I wanted a bench size for sharpening. A lot of sandy inclusions when I got this one and I had to lap away 20g to clean up the sharpening face. This one is softer and cuts slightly slower than the koppa, but particle uniformity is more consistent. Easily self slurries and dishes surprisingly quick.
- Hard/finer Aoto
- This one performs more like an Awasedo and is in the 4/5 hardness range. Super easy to use as a harder stone for burnishing out details. It readily accepts bevels on the sharpening surface without sticking, even if I put enough pressure until my finger tips turn white.
- Mikawa Nagura koppa
- This one was mined in a rare strata that borders the Botan and Koma layers. As a result, it exhibits the properties of both. The finish is coarse enough to show some scratches, but also fine at the same time to reveal banding.
- Nakayama Tomae
- Extremely hard stone and unforgiving. I'm estimating this to be 4.5/5. Too much finger pressure and you get scratches that force you back down to Nakatoishi. Dial in the finger pressure and you're awarded with a mirror like finish.
- Ohira Akapin
- Gorgeous striped pattern when wet. Feels like a 3.5/5 hardness and produces a bright semi-mirror kasumi.
Pic 1 - Bench and koppa size stones (from left to right) - Bottom row
- Ikarashi
- Very slow without slurry. Gives similar performance to the Aizu, but a touch coarser. Sharpening face is extremely clean with excellent particle uniformity. Can basically put on a finer version of the Natsuya kasumi.
- Aizu
- Final Nakatoishi before jumping to Awasedo. Cuts fast without slurry and even faster with. Great as a sanity checker for flat bevels. You can realistically stop at this stone for edges.
- Hideriyama Shiro Suita
- Finishing stone for most of my knives. As a polisher, requires precise slurry management to get a non scratchy kasumi.
- Okudo Shiro Suita
- Not for beginners. Extremely hard stone and cuts quickly without slurry. The generated swarf is completely black. Can put on the finest yet toothy edge on a blade with proper technique. Usually reserved for my single bevels or anything that I need maximum sharpness for. Will not self slurry and tends to mirror polish. Like the fine Aoto, it readily accepts bevels without sticking. Lives up to the name of King of Suita.
- Tsushima
- This one is an older piece that is harder and finer than the newer stones that are mined. As a polisher, puts on a bright kasumi that reveals banding. It is extremely competent as a finishing or pre-finishing stone
- Mizukihara Uchigumori
- Great bench stone for putting on a final finish. Rated as a 3.5/5 by Maxim at JNS. Stone is pretty forgiving of bevel geometry and finger pressure, but can release larger particles that scratch up the surface ocasionally.
- Hideriyama Tomae
- Extremely soft, coarser Awasedo that loves to generate mud. Budget friendly option for high contrast kasumi on both iron and stainlesss cladding. I used this to refinish a Kikuchiyo x Izo and the kasumi matched the OG finish.
- Aiwatani Kita
- Similar hardness to the Ohira, but a lot more difficult to use. Rated as a 3.5/5 hardness by Maxim at JNS. Blade tends to stick with the generated slurry. Produces a darker, semi-mirror kasumi.
Pic 2 - Handheld nagura (from left to right) - Top row
Some of these serve as tomo nagura to the bench stones. I use the tsushima pretty often for the final sharpening progresion with either the Hideriyama or Okudo shiro suita. The uchigumori also gets time with polishing, as it can make some stones stick less.
- Nakayama tomae
- Okudo shiro suita
- Nakayama Akapin
- Tsushima
- Uchigumori
Pic 2 - Handheld Mikawa nagura (from left to right) - Bottom row
Super useful to have these that can change the finish a bench stone normally puts on. I also use these in several of my projects to create a bright, frosted kasumi that can start to show details. For example, the Manaka x Xinguo banding was revealed by using slurry on the Meijiro.
- Ban
- Yae-Botan
- Botan
- Tenjyo
- Meijiro
- Koma
- Ungraded
If you made it this far, I applaud you. Much appreciated for reading!